Effective Column Lengths in a Rectangular Rigid Frame

Abstract

There is already presented a quantitative method to estimate the stablitity states of frame members in a global buckling. In that analysis applied to a rectangular rigid frame for the individual members, however, the resulting effective lengths of columns are different from those required in the design scheme. In this study, a rectangular frame is decomposed into those structural units which represent the axial strengths of columns stiffened with their adjacent beams. The effective column lengths are estimated upon the critical axial forces in those respective units. At the same time, to observe their interactions in a global buckling, the preceding analysis for members is generalized to deal with the stability of structural units.

On the Accordance of Frame Stability With the Effective Column Length

“…Recently in Ref. 3), it is found that a rectangular frame is exactly consisting of the structural units which stand for the respective column members stiffened with their adjoining members. Those column units have almost the same effective lengths as given in the AISC alignment charts.…”

“…In Ref 3),. the units' buckling equations are numerically solved in a variety of the bending stiffness ratio, and the critical values are shown in the effective length factor.…”